COMSAE Phase 1 Form 110 Practice Exam
Questions And Well Graded Solutions With
Rationales Updated 2026-2027
Master your COMLEX Level 1 baseline with this comprehensive review for the COMSAE Phase 1 Form
110 practice exam. This guide contains high-yield questions covering essential biomedical sciences,
pathology, pharmacology, and detailed Osteopathic Principles and Practice (OPP/OMM). Each
question features fully explained, italicized rationales to clarify core mechanisms and eliminate
distractor options. Perfect for clearing mandatory medical school benchmarks and achieving a
400+ score.
1. A 22-year-old male athlete presents with sudden onset left-sided chest pain and
dyspnea during a basketball practice. He is 6'5" and weighs 160 lbs. Physical exam
reveals decreased breath sounds and hyperresonance on the left side. What is the
most likely diagnosis?
A) Tension pneumothorax
B) Acute pulmonary embolism
C) Primary spontaneous pneumothorax
D) Mycoplasma pneumonia
Rationale: Primary spontaneous pneumothorax typically occurs in tall, thin young
males due to the rupture of subpleural apical blebs. Physical exam signs include
unilateral decreased breath sounds and hyperresonance.
2. A 45-year-old female presents with episodic right upper quadrant pain that radiates
to her right shoulder, particularly after eating fatty meals. An ultrasound reveals
gallstones without gallbladder wall thickening. What is the most likely diagnosis?
A) Acute cholecystitis
B) Biliary colic
C) Acute cholangitis
D) Choledocholithiasis
Rationale: Biliary colic presents with intermittent right upper quadrant pain radiating
to the shoulder/scapula triggered by fatty meals, caused by transient gallbladder
contraction against a stone without active inflammation.
3. A 68-year-old male with a history of hypertension presents with severe, tearing chest
pain that radiates to his back. His blood pressure is 180/100 mmHg in the right arm
and 145/85 mmHg in the left arm. What is the most likely diagnosis?
A) Acute myocardial infarction
B) Aortic dissection
, C) Pulmonary embolism
D) Acute pericarditis
Rationale: Severe, tearing or ripping chest pain radiating to the back combined with
an asymmetric blood pressure differential between the upper extremities is highly
specific for an aortic dissection.
4. A 3-year-old boy is brought to the clinic due to a barking cough and inspiratory
stridor that worsens at night. He has had a mild fever and runny nose for the past
two days. What is the most likely causative organism?
A) Respiratory syncytial virus
B) Parainfluenza virus
C) Haemophilus influenzae type b
D) Bordetella pertussis
Rationale: Croup (laryngotracheobronchitis) is characterized by a barking cough,
stridor, and hoarseness, and it is most commonly caused by the human
parainfluenza virus.
5. A 29-year-old female presents with fatigue, weight gain, constipation, and cold
intolerance. Physical exam reveals a diffuse, non-tender thyroid enlargement and
delayed relaxation of deep tendon reflexes. What is the most likely diagnosis?
A) Graves' disease
B) Hashimoto's thyroiditis
C) Subacute granulomatous thyroiditis
D) Papillary thyroid carcinoma
Rationale: Hashimoto's thyroiditis is the most common cause of hypothyroidism in
iodine-sufficient areas and characteristically presents with fatigue, weight gain, cold
intolerance, and a non-tender goiter.
6. A 62-year-old male presents with a resting tremor in his right hand that disappears
with purposeful movement. Examination reveals bradykinesia, cogwheel rigidity, and
a shuffling gait. What neurotransmitter imbalance is primary to this condition?
A) Decreased acetylcholine
B) Decreased dopamine
C) Increased serotonin
D) Decreased gamma-aminobutyric acid
Rationale: Parkinson's disease is caused by the degeneration of dopaminergic
neurons in the substantia nigra pars compacta, leading to a profound deficiency of
dopamine in the basal ganglia.
7. A 34-year-old pregnant female at 32 weeks gestation presents with sudden-onset,
painless vaginal bleeding. An ultrasound reveals the placenta is completely covering
the internal cervical os. What is the most likely diagnosis?
, A) Placental abruption
B) Placenta previa
C) Uterine rupture
D) Vasa previa
Rationale: Placenta previa classically presents as painless, bright red vaginal
bleeding in the second or third trimester when the placenta implants over the internal
cervical os.
8. A 55-year-old male smoker presents with a chronic cough productive of copious
sputum for the past 4 months. He reports a similar cough lasting 3 months during the
previous consecutive year. What is the most likely diagnosis?
A) Emphysema
B) Chronic bronchitis
C) Asthma
D) Bronchiectasis
Rationale: Chronic bronchitis is clinically defined as a chronic productive cough
lasting for at least 3 months in at least 2 consecutive years, frequently linked to
cigarette smoking.
9. A 19-year-old college student is brought to the emergency department with a high
fever, severe headache, confusion, and a petechial rash on his lower extremities.
Physical exam reveals nuchal rigidity. What is the most urgent next step in
management?
A) Brain CT scan
B) Lumbar puncture
C) Intravenous antibiotics
D) Intravenous dexamethasone
Rationale: In a patient with suspected meningococcal meningitis, empiric intravenous
antibiotic therapy must be initiated immediately after blood cultures are drawn and
should not be delayed for imaging or lumbar puncture if the patient is unstable.
10. A 52-year-old male experiences crushing substernal chest pain that radiates to his
left arm. An ECG shows ST-segment elevations in leads II, III, and aVF. Which
coronary artery is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Diagonal branch
Rationale: ST-segment elevations in leads II, III, and aVF signify an acute inferior
wall myocardial infarction, which is most commonly caused by occlusion of the right
coronary artery.
, 11. A 40-year-old female presents with bilateral, symmetric joint pain and swelling in her
hands, specifically involving the proximal interphalangeal and metacarpophalangeal
joints. She notes stiffness lasting over an hour every morning. What is the most likely
diagnosis?
A) Osteoarthritis
B) Rheumatoid arthritis
C) Gouty arthritis
D) Psoriatic arthritis
Rationale: Rheumatoid arthritis is a chronic, systemic inflammatory disease
characterized by symmetric, polyarticular joint involvement that favors the PIP and
MCP joints and causes prolonged morning stiffness.
12. A 9-month-old infant is brought to the clinic with a diffuse, maculopapular rash. His
mother notes that he had a high fever (103.5°F) for the past 3 days, which resolved
abruptly just before the rash appeared. What is the most likely diagnosis?
A) Rubeola (Measles)
B) Rubella (German Measles)
C) Roseola infantum
D) Erythema infectiosum
Rationale: Roseola infantum, caused by Human Herpesvirus 6 (HHV-6), classically
presents with a high fever that drops suddenly, immediately followed by the
appearance of a pink, maculopapular rash.
13. A 72-year-old female presents after a fall with severe pain in her right hip. Physical
exam reveals that her right lower extremity is shortened and externally rotated. What
is the most likely injury?
A) Posterior hip dislocation
B) Anterior hip dislocation
C) Femoral neck fracture
D) Acetabular fracture
Rationale: A hip fracture, particularly a displaced femoral neck fracture, typically
presents with a shortened, externally rotated leg on the affected side following low-
energy trauma in elderly patients.
14. A 26-year-old female presents with dynamic anxiety, a racing heart, and tremors
before public speaking events. She requests a medication that can help manage
these acute symptoms on an as-needed basis. Which of the following is most
appropriate?
A) Sertraline
B) Propranolol
C) Buspirone
Questions And Well Graded Solutions With
Rationales Updated 2026-2027
Master your COMLEX Level 1 baseline with this comprehensive review for the COMSAE Phase 1 Form
110 practice exam. This guide contains high-yield questions covering essential biomedical sciences,
pathology, pharmacology, and detailed Osteopathic Principles and Practice (OPP/OMM). Each
question features fully explained, italicized rationales to clarify core mechanisms and eliminate
distractor options. Perfect for clearing mandatory medical school benchmarks and achieving a
400+ score.
1. A 22-year-old male athlete presents with sudden onset left-sided chest pain and
dyspnea during a basketball practice. He is 6'5" and weighs 160 lbs. Physical exam
reveals decreased breath sounds and hyperresonance on the left side. What is the
most likely diagnosis?
A) Tension pneumothorax
B) Acute pulmonary embolism
C) Primary spontaneous pneumothorax
D) Mycoplasma pneumonia
Rationale: Primary spontaneous pneumothorax typically occurs in tall, thin young
males due to the rupture of subpleural apical blebs. Physical exam signs include
unilateral decreased breath sounds and hyperresonance.
2. A 45-year-old female presents with episodic right upper quadrant pain that radiates
to her right shoulder, particularly after eating fatty meals. An ultrasound reveals
gallstones without gallbladder wall thickening. What is the most likely diagnosis?
A) Acute cholecystitis
B) Biliary colic
C) Acute cholangitis
D) Choledocholithiasis
Rationale: Biliary colic presents with intermittent right upper quadrant pain radiating
to the shoulder/scapula triggered by fatty meals, caused by transient gallbladder
contraction against a stone without active inflammation.
3. A 68-year-old male with a history of hypertension presents with severe, tearing chest
pain that radiates to his back. His blood pressure is 180/100 mmHg in the right arm
and 145/85 mmHg in the left arm. What is the most likely diagnosis?
A) Acute myocardial infarction
B) Aortic dissection
, C) Pulmonary embolism
D) Acute pericarditis
Rationale: Severe, tearing or ripping chest pain radiating to the back combined with
an asymmetric blood pressure differential between the upper extremities is highly
specific for an aortic dissection.
4. A 3-year-old boy is brought to the clinic due to a barking cough and inspiratory
stridor that worsens at night. He has had a mild fever and runny nose for the past
two days. What is the most likely causative organism?
A) Respiratory syncytial virus
B) Parainfluenza virus
C) Haemophilus influenzae type b
D) Bordetella pertussis
Rationale: Croup (laryngotracheobronchitis) is characterized by a barking cough,
stridor, and hoarseness, and it is most commonly caused by the human
parainfluenza virus.
5. A 29-year-old female presents with fatigue, weight gain, constipation, and cold
intolerance. Physical exam reveals a diffuse, non-tender thyroid enlargement and
delayed relaxation of deep tendon reflexes. What is the most likely diagnosis?
A) Graves' disease
B) Hashimoto's thyroiditis
C) Subacute granulomatous thyroiditis
D) Papillary thyroid carcinoma
Rationale: Hashimoto's thyroiditis is the most common cause of hypothyroidism in
iodine-sufficient areas and characteristically presents with fatigue, weight gain, cold
intolerance, and a non-tender goiter.
6. A 62-year-old male presents with a resting tremor in his right hand that disappears
with purposeful movement. Examination reveals bradykinesia, cogwheel rigidity, and
a shuffling gait. What neurotransmitter imbalance is primary to this condition?
A) Decreased acetylcholine
B) Decreased dopamine
C) Increased serotonin
D) Decreased gamma-aminobutyric acid
Rationale: Parkinson's disease is caused by the degeneration of dopaminergic
neurons in the substantia nigra pars compacta, leading to a profound deficiency of
dopamine in the basal ganglia.
7. A 34-year-old pregnant female at 32 weeks gestation presents with sudden-onset,
painless vaginal bleeding. An ultrasound reveals the placenta is completely covering
the internal cervical os. What is the most likely diagnosis?
, A) Placental abruption
B) Placenta previa
C) Uterine rupture
D) Vasa previa
Rationale: Placenta previa classically presents as painless, bright red vaginal
bleeding in the second or third trimester when the placenta implants over the internal
cervical os.
8. A 55-year-old male smoker presents with a chronic cough productive of copious
sputum for the past 4 months. He reports a similar cough lasting 3 months during the
previous consecutive year. What is the most likely diagnosis?
A) Emphysema
B) Chronic bronchitis
C) Asthma
D) Bronchiectasis
Rationale: Chronic bronchitis is clinically defined as a chronic productive cough
lasting for at least 3 months in at least 2 consecutive years, frequently linked to
cigarette smoking.
9. A 19-year-old college student is brought to the emergency department with a high
fever, severe headache, confusion, and a petechial rash on his lower extremities.
Physical exam reveals nuchal rigidity. What is the most urgent next step in
management?
A) Brain CT scan
B) Lumbar puncture
C) Intravenous antibiotics
D) Intravenous dexamethasone
Rationale: In a patient with suspected meningococcal meningitis, empiric intravenous
antibiotic therapy must be initiated immediately after blood cultures are drawn and
should not be delayed for imaging or lumbar puncture if the patient is unstable.
10. A 52-year-old male experiences crushing substernal chest pain that radiates to his
left arm. An ECG shows ST-segment elevations in leads II, III, and aVF. Which
coronary artery is most likely occluded?
A) Left anterior descending artery
B) Left circumflex artery
C) Right coronary artery
D) Diagonal branch
Rationale: ST-segment elevations in leads II, III, and aVF signify an acute inferior
wall myocardial infarction, which is most commonly caused by occlusion of the right
coronary artery.
, 11. A 40-year-old female presents with bilateral, symmetric joint pain and swelling in her
hands, specifically involving the proximal interphalangeal and metacarpophalangeal
joints. She notes stiffness lasting over an hour every morning. What is the most likely
diagnosis?
A) Osteoarthritis
B) Rheumatoid arthritis
C) Gouty arthritis
D) Psoriatic arthritis
Rationale: Rheumatoid arthritis is a chronic, systemic inflammatory disease
characterized by symmetric, polyarticular joint involvement that favors the PIP and
MCP joints and causes prolonged morning stiffness.
12. A 9-month-old infant is brought to the clinic with a diffuse, maculopapular rash. His
mother notes that he had a high fever (103.5°F) for the past 3 days, which resolved
abruptly just before the rash appeared. What is the most likely diagnosis?
A) Rubeola (Measles)
B) Rubella (German Measles)
C) Roseola infantum
D) Erythema infectiosum
Rationale: Roseola infantum, caused by Human Herpesvirus 6 (HHV-6), classically
presents with a high fever that drops suddenly, immediately followed by the
appearance of a pink, maculopapular rash.
13. A 72-year-old female presents after a fall with severe pain in her right hip. Physical
exam reveals that her right lower extremity is shortened and externally rotated. What
is the most likely injury?
A) Posterior hip dislocation
B) Anterior hip dislocation
C) Femoral neck fracture
D) Acetabular fracture
Rationale: A hip fracture, particularly a displaced femoral neck fracture, typically
presents with a shortened, externally rotated leg on the affected side following low-
energy trauma in elderly patients.
14. A 26-year-old female presents with dynamic anxiety, a racing heart, and tremors
before public speaking events. She requests a medication that can help manage
these acute symptoms on an as-needed basis. Which of the following is most
appropriate?
A) Sertraline
B) Propranolol
C) Buspirone
